Firstly, you need to make sure that file and printer sharing is enabled on all networked computers.

To do this open "Network Connections" and right click the appropriate network connection - in your case it should just say "Wireless Network Connection". Select properties. You should now see a list, which should include "File and printer sharing for microsoft networks". Make sure that the checkbox next to this is ticked on all networked computers.

Now open up "Network Places" and see if anything has appeared. If there is still nothing there, oen the start menu, go to run and type \\<computer name> (where <computer name> is the name of another pc on the network)

If you need to find the network name of a computer just right click my computer and select the computer-name tab.

All you need to do is enable internet connection sharing for the broadband ISP network connection on the machine directly connected. Set DHCP for the IP address, etc for that machine's other network adapter, and the other machine's adapters. Ensure that all machines can ping each other first.